feat(dpmodel): add descriptor compression (#5592)

## Summary
- add dpmodel compression entrypoints and wire dp --dp/--jax compress
- persist and restore compressed dpmodel/JAX descriptor state, including
HLO export metadata
- implement dpmodel compression for se_e2_a, se_e2_r, and se_atten/dpa1
(with se_atten_v2 state sync)
- add common dpmodel and JAX compression coverage

## Tests
- python -m pytest source/tests/common/dpmodel/test_model_compression.py
-q
- python -m pytest source/tests/jax/test_model_compression.py -q
- python -m pytest source/tests/common/test_argument_parser.py -q
- python -m pytest source/tests/pt_expt/descriptor/test_se_r.py
source/tests/pt_expt/descriptor/test_dpa1.py
source/tests/pt_expt/descriptor/test_se_atten_v2.py -q
- python -m pytest source/tests/pt_expt/model/test_model_compression.py
-q
- ruff check .
- ruff format --check .

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
  * Added model compression support for DPModel and JAX workflows.
* Introduced a new `compress` command in the CLI for creating compressed
model files.
* Expanded support for compressed descriptors, including saving and
restoring compressed models.

* **Documentation**
* Updated CLI help text with new examples and supported model file
formats.

* **Tests**
* Added end-to-end and descriptor-level coverage for compression
behavior and model reloads.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: njzjz

deepmd/backend/dpmodel.py

@@ -34,7 +34,10 @@ class DPModelBackend(Backend):
     name = "DPModel"
     """The formal name of the backend."""
     features: ClassVar[Backend.Feature] = (
-        Backend.Feature.DEEP_EVAL | Backend.Feature.NEIGHBOR_STAT | Backend.Feature.IO
+        Backend.Feature.ENTRY_POINT
+        | Backend.Feature.DEEP_EVAL
+        | Backend.Feature.NEIGHBOR_STAT
+        | Backend.Feature.IO
     )
     """The features of the backend."""
     suffixes: ClassVar[list[str]] = [".dp", ".yaml", ".yml"]
@@ -59,7 +62,9 @@ def entry_point_hook(self) -> Callable[["Namespace"], None]:
         Callable[[Namespace], None]
             The entry point hook of the backend.
         """
-        raise NotImplementedError(f"Unsupported backend: {self.name}")
+        from deepmd.dpmodel.entrypoints.main import main as deepmd_main
+
+        return deepmd_main
 
     @property
     def deep_eval(self) -> type["DeepEvalBackend"]: